PET imaging for receptor occupancy: meditations on calculation and simplification

This invited mini-review briefly summarizes procedures and challenges of measuring receptor occupancy with positron emission tomography. Instead of describing the detailed analytic procedures of in vivo ligand-receptor imaging, the authors provide a pragmatic alJproach, along with personal perspectives, for conducting positron emission tomography imaging for receptor occupancy, and systematically elucidate the mathematics of receptor occupancy calculations in practical ways that can be understood with elementary algebra. The authors also share insights regarding positron emission tomography imaging for receptor occupancy to facilitate applications for the development of drugs targeting receptors in the central nervous system.

Recent advances in the role of toll-like receptors and TLR agonists in immunotherapy for human glioma

Gliomas are extremely aggressive brain tumors with a very poor prognosis. One of the more promising strat- egies for the treatment of human gliomas is targeted immunotherapy where antigens that are unique to the tumors are exploited to generate vaccines. The approach, however, is complicated by the fact that human gliomas escape immune surveillance by creating an immune suppressed microenvironment. In order to oppose the glioma imposed immune suppression, mol- ecules and pathways involved in immune cell matura- tion, expansion, and migration are under intensive clinical investigation as adjuvant therapy. Toll-like receptors （TLRs） mediate many of these functions in immune cell types, and TLR agonists, thus, are currently primary candidate molecules to be used as important adjuvants in a variety of cancers. In animal models for glioma, TLR agonists have exhibited antitumor proper- ties by facilitating antigen presentation and stimulating innate and adaptive immunity. In clinical trials, several TLR agonists have achieved survival benefit, and many more trials are recruiting or ongoing. However, a second complicating factor is that TLRs are also expressed on cancer cells where they can participate instead in a variety of tumor promoting activities including cell growth, proliferation, invasion, migration, and even stem cell maintenance. TLR agonists can, therefore, possibly play dual roles in tumor biology. Here, how TLRs and TLR agonists function in glioma biology and in anti-gli- oma therapies is summarized in an effort to provide acurrent picture of the sophisticated relationship of gli- oma with the immune system and the implications for immunotherapy.

Normal epigenetic inheritance in mice conceived by in vitro fertilization and embryo transfer

An association between assisted reproductive technology （ART） and neurobehavioral imprinting disorders has been reported in many studies, and it seems that ART may interfere with imprint reprogramming. However, it has never been explored whether epigenetic erros or imprinting disease susceptibility induced by ART can be inherited transgenerationally. Hence, the aim of this study was to determine the effect of in vitro fertilization and embryo transfer （IVF-ET） on transgenerational inheritance in am inbred mouse model. Mice derived from IVF-ET were outcrossed to wild-type C57BL/6J to obtain their female and male line F2 and F3 generations. Their behavior, morphology, histology, and DNA methylation status at several important differentially methylated regions （DMRs） were analyzed by Morris water maze, hematoxylin and eosin （H＆E） staining, and bisulfite genomic sequencing. No significant differences in spatial learning or phenotypic abnormality were found in adults derived from IVF （F1） and female and male line F2 and F3 generations. A borderline trend of hypomethylation was found in H19 DMR CpG island 3 in the female line-derived F3 generation （0.40±0.118, P=0.086）. Methylation status in H19/Igf2 DMR island 1, Igf2 DMR, KvDMR, and Snrpn DMR displayed normal patterns. Methylation percentage did not differ significantly from that of adults conceived naturally, and the expression of the genes they regulated was not disturbed. Transgenerational integrity, such as behavior, morphology, histology, and DNA methylation status, was maintained in these generations, which indicates that exposure of female germ cells to hormonel stimulation and gamete manipulation might not affect the individuals and their descendents.